Stress and the female brain. The effects of estradiol on the neurobiological reactions to chronic stress.

Affective disorders occur more often in women than in men. Moreover, severe instabilities in plasma estrogen levels in women, occurring postpartum and during the beginning of the perimenopausal period, are typically associated with an increased risk of the emergence of depressive symptoms and anxiety. Additionally, several studies have reported a reduction of the depressive symptoms in peri- and postmenopausal women during treatment with estrogen. Although the effects of estradiol on mood and anxiety are recognized, the exact mechanisms by which these effects are mediated remain unclear. Since there is a strong association between chronic stressful events and affective disorders in human, stress can be used as a valuable tool in animal research to characterize neurobiological mechanisms underlying major depression and/or anxiety disorders. The aim of the current thesis was to elucidate the role of estradiol on stress-related neurobiological mechanisms in female rats and to demonstrate possible protective effects on stress-induced neuronal dysfunction when estradiol was administered in a cyclic manner